The Intrinsic Shape Distribution of a Sample of Elliptical Galaxies

By J. Bak, T. Statler. 2000

229 citations recorded by the source corpus.

We apply the dynamical modeling approach of Statler to 13 elliptical galaxies from the Davies & Birkinshaw sample of radio galaxies to derive constraints on their intrinsic shapes and orientations. We develop an iterative Bayesian algorithm to combine these results to estimate the parent shape distribution from which the sample was drawn, under the assumption that this parent distribution has no preferred orientation. In the process we obtain improved estimates for the shapes of individual objects. The parent shape distribution shows a tendency toward bimodality, with peaks at the oblate and prolate limits. Under minimal assumptions about the galaxies' internal dynamics, 35% of the objects would be strongly triaxial (0.2 < T < 0.8). However, the parent distribution is sensitive to the assumed orbit populations in the galaxies. Dynamical configurations in which all galaxies rotate purely about either their long or short axes can be ruled out because they would require the sample to have a strong orientation bias. Configurations in which the mean motion about the short or long axis is either "disklike"—dropping off away from the symmetry planes—or "spheroid-like"—remaining roughly constant at a given radius—are equally viable. Spheroid-like rotation in the long-axis or short-axis tube orbits significantly lowers the abundance of prolate or oblate galaxies, respectively. If rotation in ellipticals is generally disklike, then triaxiality is rare; if spheroid-like, triaxiality is common.

Subfields: Astronomy and Astrophysics, Computer Vision and Pattern Recognition, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/293a4c4d436a8d1b6f54950eb22795d7e7d5c340

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Citations in the corpus

Modern Tests of Lorentz Invariance (2005, background): “The case of n = 3 dispersion with f (3) π = f (3) p was studied in [130, 132, 131, 48, 47, 49, 26, 16, 25, 166, 12, 167, 264, 9], while the possibility of f (3,4) π 6= f (3,4) p was studied in [154].”
The SAURON project – I. The panoramic integral-field spectrograph (2001, unknown): “…the intrinsic shapes and internal dynamical and stellar population structure of elliptical galaxies and spiral bulges is a long-standing problem, the solution of which is tied to understanding the processes of galaxy formation and evolution (Franx, Illingworth & de Zeeuw 1991; Bak & Statler 2000).”
The shapes of galaxies in the Sloan Digital Sky Survey (2008, unknown): “Spatially resolved observations of internal kinematics can sort out the three-dimensional shape of a galaxy (Binney 1985; Franx, Illingworth & de Zeeuw 1991; Statler 1994a,b; Statler & Fry 1994; Bak & Statler 2000; Statler, Lambright & Bak 2001).”
THE EXTRAGALACTIC BACKGROUND LIGHT, THE HUBBLE CONSTANT, AND ANOMALIES: CONCLUSIONS FROM 20 YEARS OF TeV GAMMA-RAY OBSERVATIONS (2015, methodology): “We investigate in this section the compatibility of the 86 spectra in the gamma-ray cosmology sample with a quantumgravity induced effect such as proposed by Kifune (1999), Aloisio et al. (2000), Protheroe & Meyer (2000), Ellis et al. (2001), Amelino-Camelia & Piran (2001), Stecker & Glashow (2001).”
THE COSMIC INFRARED BACKGROUND: Measurements and Implications ⁄ (2001, background): “(2) Kifune (1999) noted that because the photon energy-momentum relation violates Lorentz invariance in quantum gravity scenarios (Amelino-Camelia et al 1998, and references therein), the energy threshold for electron pair production can be raised, thus reducing the opacity of the universe to TeV…”
The SAURON project — II. Sample and early results (2001, unknown): “…the incidence of kinematically decoupled cores, embedded disks, and minor axis rotation, and will also provide parametrized input for statistical studies of, e.g., the distribution of intrinsic shapes (Franx, Illingworth & de Zeeuw 1991; Bak & Statler 2000) and the construction of dynamical models.”
Quantum-Spacetime Phenomenology (2008, background): “of the cutoff is naturally obtained [327, 38, 463, 73] in frameworks with the structure of Eq.”
New limits on the density of the extragalactic background light in the optical to the far-infrared from the spectra of all known TeV blazars (2007, background): “The so-calledpile-up at high energies was first noticed by Protheroe & Meyer (2000) for the Mkn 501 spectrum, and early attempts to avoid it invoked violation of the L rentz invariance (Kifune 1999; Protheroe & Meyer 2000).”